<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        body {
            margin: 0px;
        }

        .nav-bar {
            background-color: #545c64;
            color: white;
            /* font-size: 0px; */
            /* padding: 0px 60px; */

        }

        .nav-bar .btn {
            display: inline-block;
            min-width: 100px;
            text-align: center;
            font-size: 20px;
            margin-right: 30px;
            padding: 20px 0px;
            box-sizing: border-box;
            cursor: pointer;
            user-select: none;
            border-bottom: 4px solid transparent;
            position: relative;

        }
        .nav-bar .btn:hover{
            border-color:#f7ca4b ;
        }
         .nav-bar .btn:hover span{
            color:#f7ca4b ;
         }
         .nav-bar .btn:hover .btn-items {
            display: block;
        }
        .nav-bar .btn .btn-items-box {
            position: absolute;
            padding: 30px 0px 0px 0px;
            transform: translate(40px,0px);
        }
         
        .nav-bar .btn .btn-items{
            background-color:#545c64 ;
            margin: 0px;
            padding: 0px;
            list-style: none;
            min-width: 200px;
            text-align: left;
            padding: 10px 0px;
            border-radius: 4px;
            box-shadow: 0px 0px 4px #6e7276;
            display: none;
        }
         .nav-bar .btn .btn-items li {
            padding: 10px 14px;
            font-size: 16px;
            cursor: pointer;
        }
        
        .nav-bar .btn .btn-items li:hover {
            background-color: #434a50;
        }
    </style>
</head>

<body>

    <nav class="nav-bar">
        <div class="btn">
            <span>导航1</span>
            <div class="btn-items-box">
                <ul class="btn-items">
                    <li>选项1</li>
                    <li>选项2</li>
                    <li>选项3</li>
                    <li>选项4</li>
                </ul>
            </div>
        </div>
        <div class="btn">
            <span>导航2</span>
            <div class="btn-items-box">
            <ul class="btn-items">
                <li>选项1</li>
                <li>选项2</li>
                <li>选项3</li>
                <li>选项4</li>
            </ul>
        </div>
        </div>
        <div class="btn">
            <span>导航3</span>
            <div class="btn-items-box">
            <ul class="btn-items">
                <li>选项1</li>
                <li>选项2</li>
                <li>选项3</li>
                <li>选项4</li>
            </ul>
        </div>
        </div>
        <div class="btn">
            <span>导航4</span>
            <div class="btn-items-box">
            <ul class="btn-items">
                <li>选项1</li>
                <li>选项2</li>
                <li>选项3</li>
                <li>选项4</li>
            </ul>
        </div>
        </div>
    </nav>
</body>

</html>